"But in the middle Stage of Life, or it may be from fifteen to fifty Years of Age, the Memory is generally in its happiest State, the Brain easily receives and long retains the Images and Traces which are impress'd upon on it, and the natural Spirits are more active to range these little infinite unknown Figures of Things in their proper Cells or Cavities, to preserve and recollect them."
— Watts, Isaac (1674-1748)
Whatsoever therefore keeps the Brain in its best Temper and Consistence may be a Help to preserve the Memory: But Excess of Wine or Luxury of any Kind, as well as Excess in the Studies of Learning or the Businesses of Life, may overwhelm the Memory by overstraining and weakening the Fibres of the Brain, over-wasting the Spirits, injuring the true Consistence of that tender Substance, and confounding the Images that are laid up there.
Most text drawn from Google Books. See The Improvement of the Mind: or, a Supplement to the Art of Logick: Containing a Variety of Remarks and Rules for the Attainment and Communication of Useful Knowledge, in Religion, in the Sciences, and in Common Life. By I. Watts, D.D. (London: Printed for James Brackstone, at the Globe in Cornhill, 1741). <Link to ESTC><Link to 2nd edition in Google Books>